Wrong Differential Gasket And Cover ?

killian96ss · Post by **killian96ss** » Fri Nov 14, 2003 8:04 am

I'm not sure if this has been discussed before, but I'll mention it anyway. GM has been installing the wrong differential cover gasket on all 10 bolt rear ends for at least 10 years now. I just put on a new Summit aluminum rear end cover with bearing cap preload bolts last night and noticed that the factory gasket and even the factory cover are completely blocking the side oiling holes for the wheel bearings! I found this same problem on my 10 bolt equiped 96 Impala SS. I know most of the people in the Impala / Caprice community have known of this problem ever since they started making them. I just recently read a thread on the Impala SS forum that states all 10 bolt rear ends both cars and trucks have this incorrect gasket. Basically your wheel bearings will fail much sooner than they should because of the inadequate oiling. Even the gasket I got with the Summit cover had the holes blocked, so I put the gasket on the rear end and marked the holes and cut them out. I even filed my own oiling holes into the aluminum cover to be sure my bearings are getting oil. So, the next time anyone here is changing their rear end fluid or putting on an aftermarket cover take a look at the oiling holes and you'll see what I mean. BTW, GM does not admit to the problem, so you probably won't be able to have then cover it under warranty, even though the problem is very obvious. Hope this info helps, Steve K.

kwalsh · Post by **kwalsh** » Fri Nov 14, 2003 8:13 am

I apologize for the ignorance here:
What do you mean by oiling holes?
I changed the rear diff gasket/gear oil and I didn't notice any holes
being blocked by the new gasket.

Post by **HenryJ** » Fri Nov 14, 2003 8:36 am

Sorry, but I have to plead ignorance here too.

Do you have a link to the SS information? How about some pictures , or a diagram?

Which bearings are we discussing outer wheel bearings, side differential carrier bearings, pinion bearings,

killian96ss · Post by **killian96ss** » Fri Nov 14, 2003 8:44 am

The holes are on the outside of each bearing cap. If you were to imagine a centerline that runs horizontal through the rear end then you would see the 2 holes I'm talking about. Each hole is perfectly round and is about 3/8 to 1/2 inch in diameter. Hope this helps, Steve

Retep · Post by **Retep** » Fri Nov 14, 2003 8:53 am

Also covered at the ZR2 site
Locking diff FAQ

Pete

Made the long url a link-HJ[/b]

Dragonmaster · Post by **Dragonmaster** » Fri Nov 14, 2003 8:54 am

killian96ss wrote:The holes are on the outside of each bearing cap. If you were to imagine a centerline that runs horizontal through the rear end then you would see the 2 holes I'm talking about. Each hole is perfectly round and is about 3/8 to 1/2 inch in diameter. Hope this helps, Steve

Doesn't help at all, a pic or link to the ss forum would be nice

killian96ss · Post by **killian96ss** » Fri Nov 14, 2003 10:01 am

HenryJ wrote:Do you have a link to the SS information? How about some pictures , or a diagram?

Which bearings are we discussing outer wheel bearings, side differential carrier bearings, pinion bearings,

I will try to find the link and some pictures. The holes are on either side of the side differential carrier bearings, and are blocking fluid from reaching the outer wheel bearings. Hope this helps, Steve

killian96ss · Post by **killian96ss** » Fri Nov 14, 2003 10:39 am

Here is one link that explains the problem, and I'll try to find more in case this one isn't clear or doesn't work. http://www.socalss.org/special/holes.htm

Dragonmaster · Post by **Dragonmaster** » Fri Nov 14, 2003 11:22 am

that's clear enough for me. Now that I know about this I may just have to pay closer attention next time I do a rear end fluid change and see if I have those holes.

a2b · Post by **a2b** » Fri Nov 14, 2003 1:56 pm

oops.

sorry to keep you guys out of the loop. i knew about this along time ago. i just kept it a secret

i didnt know but i just dont care

Post by **HenryJ** » Fri Nov 14, 2003 4:09 pm

killian96ss wrote:Here is one link that explains the problem, and I'll try to find more in case this one isn't clear or doesn't work. http://www.socalss.org/special/holes.htm

Thanks, That explains the point.

Retep wrote:ZR2.com FAQ

Is a really good explanation also. And shows that a cover is available for the 8.5" rear

I guess it is a "NON" option for us , since the 7.625" cover does not have "bulges" in the cover to accommodate opening of the holes. Our stock cover and all the aftermarket covers that I have seen do not have any access for the holes, so it is not an issue IMO.

Now if an aftermarket company is paying close attention {hint} it might be another selling point for an aftermarket cover

Dragonmaster · Post by **Dragonmaster** » Sat Nov 15, 2003 3:29 pm

It wouldn't be that hard to fix on a stock cover, just put a monster weld in the general area on the outside and drill a hole. to line up on the inside on an angle

Post by **HenryJ** » Sat Nov 15, 2003 4:01 pm

Dragonmaster wrote:It wouldn't be that hard to fix on a stock cover, just put a monster weld in the general area on the outside and drill a hole. to line up on the inside on an angle

Sounds easy?

Even though the monster weld would not only warp the "stuff" out of the cover but also be very likely to leak from the tiny holes created in the weld, hardened area in the heat effected zone cracking , or the weld itself cracking due to the lack of flexability. You think you have an oiling problem now , wait till you try sumthin' like that

Now a "channel" could be welded to the exterior then the interior cut away to expose the hole. Same warping consern, it would not leave much of the flange to seal the cover (approx. 1/4") and a whole bunch of work for a pretty small return.

killian96ss · Post by **killian96ss** » Sat Nov 15, 2003 5:00 pm

I just recently put on a Summit aluminum differential cover with the bearing cap preload bolts and it also had the oiling holes blocked. What I did to correct this problem was put the gasket on the rear end with the cover off and lined up all 10 of the cover holes and pressed lightly on the gasket over the lubing holes to create an impression of the holes so that I could cut out the holes with an exacto knife. After I did this I laid the gasket on the new aluminum cover and marked the area that needed to cut out. I used a large half round file and made an oiling channel on each side that matched up with the holes I cut in the gasket. IMO this will provide more than adequate oiling for the wheel bearings. As an added benifit the cover has 600 tons of support and keeps the bearing caps from flexing or breaking when under load, and will definitely help protect the gears from rocks and stuff when off roading. It also looks very cool. I wish I had done some install pics for everyone to see, but if you want to see what the covers look like just go to Summit's web site and look up differential covers. Thses covers are very nice and come with the gasket and ARP 12 point stainless bolts for only $139. I think this is a great mod for improving the strength and reliability of the 10 bolt rear end. I hope this info is helpfull, and remember GM will deny that there is any problem at all which really sucks because it affects so many cars and trucks with the 10 bolt.

Post by **HenryJ** » Sat Nov 15, 2003 5:11 pm

killian96ss wrote:I just recently put on a Summit aluminum differential cover...

Nice! That cover has the extra material in just the right place. And fill / drain holes too.

killian96ss · Post by **killian96ss** » Thu Jan 22, 2004 7:32 am

Here is a picture of the Summit aluminum Diff. cover that I put on my Crew.

2bunik · Post by **2bunik** » Sat Jan 01, 2005 1:15 pm

Just a thought

wouldn't a 1994-1996 impala cover or an s-10 of the same year work on our trucks. it would be a direct bolt on wouldnt it? I am just trying to see some options here ..

Post by **HenryJ** » Sat Jan 01, 2005 2:01 pm

2bunik wrote:Just a thought
wouldn't a 1994-1996 impala cover or an s-10 of the same year work on our trucks. it would be a direct bolt on wouldnt it? I am just trying to see some options here ..

That may not work. The 8.5" and 7.625" covers do not interchange.

HenryJ wrote:the 7.625" cover does not have "bulges" in the cover to accomidate opening of the holes.

2bunik · Post by **2bunik** » Sat Jan 01, 2005 10:55 pm

if ours are the 7.625.. wouldn't the earlier s-10s have the same rear-end?

I am confused..
ok I am under the impression that the earlier s-10s DID have bulges and the same rear as our current newer trucks..(except our newer trucks do not have bulges..) correct?

I can now see if the impala is a 8.5 why they wouldn't interchange..

Or is the summit cover the only way to go here?

killian96ss · Post by **killian96ss** » Mon Jan 03, 2005 11:40 am

2bunik wrote:if ours are the 7.625.. wouldn't the earlier s-10s have the same rear-end?

As far as 10 bolt rears there is 7.5", 7.625", 8.2", and 8.5". I'm not sure what the earlier S10's have, but the problem is not only the cover but the gasket that GM uses that doesn't have the oiling holes cut out. I don't know the exact year GM stopped using the correct gasket or cover, but it has been at least 10 years.

I can now see if the impala is a 8.5 why they wouldn't interchange..

Or is the summit cover the only way to go here?

I happen to like the Summit cover, but there are many more options. Even with the Summit cover, I did file a few oiling grooves to make it work a little better.

Steve

2bunik · Post by **2bunik** » Mon Jan 03, 2005 12:04 pm

As much as I really like the beefy summit one. I am only looking to correct the oiling problem ,not trying to spend too much on the cover. Not if there is a cheaper way to correct the malfunction..

Post by **HenryJ** » Mon Jan 03, 2005 12:44 pm

2bunik wrote:As much as I really like the beefy summit one. I am only looking to correct the oiling problem ,not trying to spend too much on the cover. Not if there is a cheaper way to correct the malfunction..

I do not know of any other options at this point.

The problem lies in opening the area to those holes. All the stock covers cover the holes. You would need to add a piece to open this area and cut out the interior for clearance. This just doesn't work very well on a sheet metal cover. I am sure it could be done, but not easily. I'd have my doubts as to durability and sealing.

One of the information links above describes the flexible nature of the 7.5" and 7.625" cases. This is a good reason to make the switch to a "trussed" cover. The other is of course they add material in just the right place to file a relief for opening up the holes.

I think this mod is going to require a cast aluminum cover. So now the questions should be what is the least expensive cover that can be purchased to achieve this?

Jim added a nice cover to his , but I'm not sure what it's cost was - Jim's cover one like his is selling on ebay right now- Cool cover currently at $40

F9K9 · Post by **F9K9** » Fri Oct 06, 2006 6:56 pm

Is the white arrow pointing at one of the oiling holes in question?

Thanks,

Reed

Post by **HenryJ** » Sat Oct 07, 2006 5:49 am

Yes. Those allow the oil to enter the axle tubes without passing through the carrier bearings.

gofast505 · Post by **gofast505** » Tue Nov 14, 2006 1:23 pm

Does anyone have the link on summits site this cover? I think it may have been removed.

F9K9 · Post by **F9K9** » Tue Nov 14, 2006 2:05 pm

Summit Diff Cover

gofast505 · Post by **gofast505** » Tue Nov 14, 2006 2:37 pm

I found that link too, that is for the 7.5, are they interchangable with the 7.625 ?

I notices that in the image HeneryJ posted has an _m at the end, so the images are different.

bl

F9K9 · Post by **F9K9** » Tue Nov 14, 2006 2:43 pm

I just went through this and they work on our rear differentials. Brule has a different brand.

MyWhiteKnight · Post by **MyWhiteKnight** » Sat Aug 22, 2020 8:01 am

Hey folks, it has been awhile since I signed-in, prolly because my crewcab has only 45,000 miles and hasn't needed much aside from dry rot/lot rot. I recently installed Proform's awesome Bowtie rear differential cover with bearing cap preload bolts. I filed oiling slots into the inside edges for the bearings to receive oil. Unlike some amazon reviewers, the black exterior paint did not pop-off when I torqued the cover bolts. I assume they were applying too much torque, maybe. In my search for a gasket that would also allow for oiling of the bearing holes, I came across; LubeLocker for GM Chevy 7.5" 10-Bolt Differential Cover Gasket - LLR-G750. It was a perfect fit, easy install, no leaks, no RTV mess, and worth every penny. The pre-installed sealant was perfectly positioned so that I could trim the gasket to allow for a small amount of fluid to reach the oiling holes for the wheel bearings. The gasket is more expensive than what we have been using, but after installing it and realizing that I won't be scraping RTV later...It is worth it IMO. I don't know if I personally would reuse it after removing it later, but the mfg. claims it can be reused.

https://www.proformparts.com/product-de ... ck-crinkle

https://www.lubelocker.com/collections/ ... e-llr-g750

S-10CREWCAB.NET

Wrong Differential Gasket And Cover ?

Wrong Differential Gasket And Cover ?

Re: Wrong Differential Gasket And Cover ?